Azure DocumentDB vs eXist-db

Azure DocumentDB is a document database for applications using BSON and JSON. It supports transactions and vector search, with a maximum document size of 16.0 MB. Deployment options include managed cloud and another deployment model; listed platforms are Linux, macOS, and Windows. The Free Tier is billed Free for the life of the cluster and includes 32 GB of storage and one free database server per subscription. Fixed M-series plans provide different node capacities: M10 starts with 1 vCore and 2 GiB of memory per node, while M300 lists 96 vCores and 384 GiB per node. Between those are configurations with varying memory and compute, including burstable vCores on M25. M200-Autoscale is billed hourly according to usage and offers up to 64 vCores and 256 GiB of memory. Prices for the listed paid tiers are displayed as $-, with actual amounts depending on region and currency. This gives prospective users concrete capacity specifications alongside the free cluster allowance.

eXist-db is a free, open-source NoSQL document database and application platform centered on XML. Its native engine stores textual or binary documents without requiring a database schema, and it is designed for self-hosted deployment on Linux, macOS, or Windows. The product implements XQuery 3.1, though some features and functions are unsupported, and RESTXQ lets developers deploy RESTful services from XQuery annotations. Its interfaces include REST-style HTTP, SOAP, XML-RPC, and WebDAV. A browser-based IDE provides syntax coloring, code completion, and error checking for application artifacts. Full-text search uses an implementation-specific Apache Lucene approach rather than the W3C XQuery and XPath Full Text 3.0 specification. Security extends Unix permissions with access control lists and external authentication realms. The software is licensed under the LGPL for academic, non-commercial, and commercial use. The documentation lists Java 8 for versions 3.x–6.x or Java 21 for version 7.x, about 500 MB of disk space, and at least 512 MB of memory.